Acoustic imaging of objects in liquids using a matrix of rod waveguides

There are several acoustic imaging methods for studying opaque liquids with thermal inhomogeneities, for example, aggressive chemically active liquids and molten metals, where the use of electromagnetic waves is often difficult or simply impossible, and the use of acoustic transducers for receiving ultrasonic waves involves difficulties. The main problem in this case is the protection of the piezoelectric transducer from the influence of an aggressive environment and the relatively low sensitivity of high-temperature receiving piezoelectric sensors, which complicates the use of traditional ultrasound imaging systems. In this paper, we propose a method for detecting and visualizing objects using a scanning echo-pulse system, in which acoustic signals are received through waveguides in the form of steel rods. The echo pulse can be emitted into a liquid using a high-temperature piezoelectric transducer that can withstand such harsh conditions, or through a rod waveguide, the end of which is in an environment with safe working conditions. This end is the source of the ultrasonic signal. The other end is immersed in an aggressive liquid and brought to the investigated area to probe it. To register an ultrasonic echo signal reflected from the investigated object, a multichannel waveguide system is used in the form of a bundle of metal rods, one end of which is located near the visualization object, providing a wide viewing angle and high resolution. The rods are long enough, so that the second end of the specified bundle is located outside the aggressive fluid, where it is already possible to receive signals by traditional methods.